package com.marui.ch8a.marui;

import java.util.concurrent.ConcurrentHashMap;

public class MyTest {
    public static void main(String[] args) {
        ConcurrentHashMap<String, String> map = new ConcurrentHashMap<>();
        System.out.println(map.putIfAbsent("admin","123"));
        System.out.println(map.putIfAbsent("super","456"));
        System.out.println(map.putIfAbsent("hehe","ganjimao"));
        System.out.println(map.putIfAbsent("super","4567"));
    }
}
